they have warned the syrian government not to use disproportionate force, yet clearly disproportionate force has been and is being used in this conflict 21 months on, 40,000-plus dead. now, in terms of what will happen next, it's hard to know on the ground here. the rebels are clearly making advances. the north of this country feels like an independent state. aside from attacking from the air, there are not any syrian troops in this area at all, but the rebels still don't have enough power to deliver a knockout blow. most of the fighting is focused on the two big cities, aleppo and damascus. but as of now, they haven't been able to take either one of them. david? >> richard engel, thank you very much. for more on this developing story, i want to go to "the atlantic's" jeffrey goldberg, also a columnist for bloomberg view, and helene cooper. welcome to both of you. jeffrey, you covered this region extensively and have for years. you heard what the president has said and what richard has said. why this red line? something the united states never did in iraq, for instance, when hussein us